I can’t recall him previously engaging in explicit sex on the silver screen.

You’d think that being rich, famous and a movie star, you’d be willing and able to spend half of your life under the duvet with the most curvaceous queens of Hollywood and only a director shouting ‘cut’ for company.

But no. In truth, it’s surprising how conservative Hollywood still is when it comes to mainstream love action. Until now...

Carrey was originally given his first break by Clint Eastwood in The Dead Pool (1988).

For a 48-year-old granddad, he’s certainly in admirable shape for hot pants.

And I’ve always thought there was more to him than meets the eye – that he could, one day, win an Oscar given the right script and director.

Trouble is, for every foot Carrey has put in the Academy Awards’ base camp like The Truman Show (1998) or Eternal Sunshine (2004), he’s made something like When Nature Calls or Fun With Dick and Jane.

In 20 years of work, he’s barely made a dozen reasonably watchable high-profile movies.

And here, all too often, he’s simply recyling the dafter sides to his previous characters.

Then there’s Ewan McGregor, once the next big thing after Trainspotting, but whose nightmarishly-wooden performances in the Star Wars movies must still haunt him deep down.

In many other films he appears to be a grinning maniac – like Jack Nicholson minus the edge thanks to a bottle of laughing gas.

His best performances were in Moulin Rouge! (2001) and in the little-seen Young Adam (2003), but who’d want to sit through the likes of Down With Love (2003) or Cassandra’s Dream (2007) ever again?

Here, following his gay roles in Velvet Underground and Scenes of a Sexual Nature, McGregor becomes the titular object of Steven’s affections in jail.

It never feels like the odd couple really are in prison because life there seems to be too bright – just like their uniforms.

But for Hollywood to go down the road of having two such big names even considering a kiss is a sign of how times have changed.

One couldn’t imagine Messrs Schwarzenegger, Stallone and Willis puckering up at the height of their careers, nor would it have been credible had it even been seen as an option.

Carrey and McGregor’s relationship is believable in that respect, though quite what Jim does to his barnet without getting any reaction is anybody’s guess.

Written and directed by the Bad Santa (2003) team of John Requa and Glenn Ficarra, the big trouble with I Love You Phillip Morris is that they are trying to have their cake as well eat it.

They want to break down sexual barriers while making a romcom and a con movie all at the same time.

But rarely do they ever make you feel as if they know which is more important.

True or not, the Phillip Morris story doesn’t feel as engaging as Spielberg’s Catch Me If You Can (featuring the superior pairing of Tom Hanks and Leonardo DiCaprio in 2002) or even Lasse Hallström’s under-appreciated movie The Hoax (2006), in which Richard Gere plays Clifford Irving who tries to sell a bogus biography of Howard Hughes.

But Carrey’s fans (more than Ewan’s) will certainly be surprised by this, especially if they are willing to take an open mind ready to expect the unexpected during some of the more explicit scenes.